Device and method for measuring trace ions in pure water

Abstract

The invention discloses a device and a method for measuring trace ions in pure water. The device comprises a first multi-way switching valve and a second multi-way switching valve, wherein a quantitative loop, a sample injection needle and a chromatographic column are arranged on the first multi-way switching valve; a concentration column and a first chromatographic pump are arranged on the first multi-way switching valve; the second multi-way switching valve is further connected with the first multi-way switching valve. A second chromatographic pump and a cleaning container are arranged on the third multi-way switching valve; the third multi-way switching valve is further connected with the second multi-way switching valve. The fourth multi-way switching valve is respectively connected with the second multi-way switching valve and the third multi-way switching valve; the fourth multi-way switching valve is configured to switch the liquid output by the sample injection needle or the cleaning container to flow to the concentration column or the waste liquid container; a purifier is further arranged between the fourth multi-way switching valve and the third multi-way switching valve. And the requirement of trace detection in pure water is met.

Description

Technical Field

[0001] The present invention relates to the technical field of ion chromatography detection, in particular to a device for determining trace ions in pure water and a determination method thereof. Background Art

[0002] Pure water refers to H2O free of impurities. Academically, pure water, also known as high-purity water, refers to water of extremely high chemical purity. It is primarily used in fields such as biology, chemical engineering, metallurgy, aerospace, and electricity. However, since these industries have very high purity requirements, the electronics industry is the most common application.

[0003] During the preparation of pure water, anions and cations in the water are removed using techniques such as electrodialysis, reverse osmosis, and ion exchange resins. After preparation, the pure water needs to be tested. Typically, this is done using ion chromatography. However, due to the high purity of pure water, the residual ion content in pure water is extremely low. Therefore, when sampling and testing with an ion chromatograph, it is difficult to accurately detect trace amounts of ions in pure water.

[0004] In view of this, how to design a technology that meets the requirements of trace ion chromatography detection in pure water and improves detection accuracy is the technical problem to be solved by the present invention. Summary of the Invention

[0005] The present invention provides a device for determining trace ions in pure water and a method thereof, which can meet the detection requirements of trace ions in pure water and improve the detection accuracy.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a device for measuring trace ions in pure water, comprising: a first multi-way switching valve, wherein the first multi-way switching valve is provided with a quantitative loop, an injection needle and a chromatographic column, and the injection needle, the quantitative loop and the chromatographic column are respectively connected to corresponding connection ports of the first multi-way switching valve; a second multi-way switching valve, wherein the first multi-way switching valve is provided with a concentrating column and a first chromatographic pump, the concentrating column and the first chromatographic pump are respectively connected to corresponding connection ports of the second multi-way switching valve; the second multi-way switching valve is also connected to the first multi-way switching valve; a third multi-way switching valve, wherein the third multi-way switching valve is provided with a second chromatographic pump and a cleaning container, wherein the cleaning container is configured to store cleaning water; the second chromatographic pump and the cleaning container are respectively connected to corresponding connection ports of the third multi-way switching valve; and the third multi-way switching valve is also connected to the second multi-way switching valve; a fourth multi-way switching valve, the fourth multi-way switching valve being connected to the second multi-way switching valve and the third multi-way switching valve, respectively; the fourth multi-way switching valve being configured to switch the liquid output from the injection needle or the cleaning container to flow to the concentrating column or the waste liquid container; A purifier is further provided between the fourth multi-way switching valve and the third multi-way switching valve.

[0007] Furthermore, in the cleaning mode, the cleaning container, the third multi-way switching valve, the second chromatographic pump, the fourth multi-way switching valve, the second multi-way switching valve, the concentration column and the waste liquid container are connected in sequence.

[0008] Furthermore, the cleaning liquid output from the cleaning container flows into the second chromatographic pump through the third multi-way switching valve; The cleaning liquid output from the second chromatographic pump flows through the third multi-way switching valve, the fourth multi-way switching valve, and the second multi-way switching valve in sequence and flows into the concentration column; The cleaning liquid flowing out of the concentrating column flows into the waste liquid container through the second multi-way switching valve.

[0009] Furthermore, in the rinse mode, the injection needle, the first multi-way switching valve, the second multi-way switching valve, the third multi-way switching valve, the second chromatographic pump, the fourth multi-way switching valve and the waste liquid container are connected in sequence.

[0010] Furthermore, the sample solution outputted by the injection needle passes through the first multi-way switching valve, the second multi-way switching valve, and the third multi-way switching valve in sequence and enters the second chromatographic pump; The sample solution output from the second chromatographic pump flows into the waste liquid container through the third multi-way switching valve and the fourth multi-way switching valve.

[0011] Furthermore, in the enrichment mode, the injection needle, the first multi-way switching valve, the third multi-way switching valve, the second chromatographic pump, the fourth multi-way switching valve, the second multi-way switching valve, the concentration column and the waste liquid container are connected in sequence.

[0012] Furthermore, the sample solution outputted by the injection needle passes through the first multi-way switching valve, the second multi-way switching valve, and the third multi-way switching valve in sequence and enters the second chromatographic pump; The sample solution output from the second chromatographic pump flows into the concentration column through the third multi-way switching valve, the fourth multi-way switching valve, and the second multi-way switching valve in sequence; The sample solution flowing out of the concentrating column flows into the waste liquid container through the second multi-way switching valve.

[0013] Furthermore, in the elution mode, the first chromatographic pump, the second multi-way switching valve, the concentration column, the first multi-way switching valve, the quantitative loop and the chromatographic column are connected in sequence.

[0014] Furthermore, the eluent output by the first chromatographic pump sequentially flows into the concentration column through the second multi-way switching valve; The eluent output from the concentrating column flows into the quantitative loop through the second multi-way switching valve and the first multi-way switching valve; The eluent output from the quantitative loop flows into the chromatographic column through the first multi-way switching valve.

[0015] The present invention also provides a detection method of the above-mentioned device for determining trace ions in pure water, comprising: an injection mode, a flushing mode, an enrichment mode and an elution mode; In the injection mode, the sample solution is injected into the quantitative loop through the injection needle; In the cleaning mode, the cleaning liquid flows through the third multi-way switching valve, the second chromatographic pump, the fourth multi-way switching valve, and the second multi-way switching valve in sequence and enters the concentrating column for cleaning; In the rinse mode, the sample solution is sucked in through the injection needle and flows through the first multi-way switching valve, the second multi-way switching valve, the third multi-way switching valve, the second chromatographic pump, and the fourth multi-way switching valve in sequence; In the enrichment mode, the sample solution is injected into the concentrator column through the injection needle; In the elution mode, the eluent flows through the first chromatographic pump, the second multi-way switching valve, the concentration column, the first multi-way switching valve, the quantitative loop and the chromatographic column in sequence.

[0016] By configuring multiple multi-way switching valves, the flow path can be switched according to different working modes. The first chromatographic pump is used to enrich sufficient ions in pure water on the concentration column, and then the eluent is transported by the first chromatographic pump to elute the concentration column and transport it into the chromatographic column for ion chromatography detection. As for the second chromatographic pump, during use, on the one hand, the cleaning liquid can be transported by the second chromatographic pump to clean the multi-way switching valve and the concentration column. On the other hand, after the multi-way switching valve is switched, the second chromatographic pump injects the pure water to be tested through the injection needle to use the pure water sample to clean the multi-way switching valve and the connecting pipes between the multi-way switching valves. In this way, it is possible to avoid large errors in the actual detection process due to excessive ion content in the cleaning liquid during the cleaning process. The second chromatographic pump is used to rinse the multi-way switching valve and the connecting pipes with the pure water sample to be tested to minimize the influence of external ions, and to maximize the ions enriched in the concentration column from the pure water sample to be tested, thereby meeting the detection requirements of trace ions in pure water and improving the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the device for measuring trace ions in pure water in the flushing mode of the present invention; Figure 2This is a schematic diagram of the device for determining trace ions in pure water in the present invention in the rinse mode; Figure 3 This is a schematic diagram of the device for determining trace ions in pure water in the enrichment mode of the present invention; Figure 4 This is a schematic diagram of the device for determining trace ions in pure water in the elution mode of the present invention; Figure 5 This is a schematic diagram of the device for determining trace ions in pure water in the standard sample injection mode of the present invention.

[0018] Reference numerals: 1. First multi-way switching valve; 11. Quantitative loop; 12. Injection needle; 13. Chromatographic column; 14. Third chromatographic pump; 2. Second multi-way switching valve; 21. Concentration column; 22. First chromatography pump; 3. Third multi-way switching valve; 31. Second chromatography pump; 32. Cleaning container; 4. The fourth multi-way switching valve; 5. Waste liquid container; 6. Purifier. DETAILED DESCRIPTION

[0019] like Figure 1-Figure 5 As shown, the present invention provides a device for measuring trace ions in pure water, comprising: A first multi-way switching valve 1 is provided with a quantitative loop 11, an injection needle 12 and a chromatographic column 13, and the injection needle 12, the quantitative loop 11 and the chromatographic column 13 are respectively connected to corresponding connection ports of the first multi-way switching valve 1; A second multi-way switching valve 2, wherein the first multi-way switching valve 1 is provided with a concentration column 21 and a first chromatography pump 22, the concentration column 21 and the first chromatography pump 22 are respectively connected to corresponding connection ports of the second multi-way switching valve 2; the second multi-way switching valve 2 is also connected to the first multi-way switching valve 1; A third multi-way switching valve 3 is provided with a second chromatographic pump 31 and a cleaning container 32, wherein the cleaning container 32 is configured to store cleaning water; the second chromatographic pump 31 and the cleaning container 32 are respectively connected to corresponding connection ports of the third multi-way switching valve 3; the third multi-way switching valve 3 is also connected to the second multi-way switching valve 2; The fourth multi-way switching valve 4 is connected to the second multi-way switching valve 2 and the third multi-way switching valve 3 respectively; the fourth multi-way switching valve 4 is configured to switch the liquid output from the injection needle 12 or the cleaning container 32 to flow to the concentration column 21 or the waste liquid container 5.

[0020] Specifically, the trace ion determination device in pure water is equipped with four multi-way switching valves, which can meet the requirements of sampling, cleaning, rinsing, enrichment and elution during the pure water detection process.

[0021] The quantitative ring 11 is connected to two corresponding connection ports on the first multi-way switching valve 1 , and the corresponding connection port of the first multi-way switching valve 1 is also connected to the injection needle 12 and the corresponding connection port of the second multi-way switching valve 2 through a pipeline.

[0022] During actual use, four or more switching valves can cooperate with each other to achieve pure water cleaning of the concentration column 21, rinse the detection flow path with samples, enrich the samples through the concentration column 21, and finally elute the concentration column 21 to achieve ion chromatography analysis and detection.

[0023] Preferably, a purifier 6 is further provided between the fourth multi-way switching valve 4 and the third multi-way switching valve 3 .

[0024] Specifically, the water flowing out of the fourth multi-way switching valve 4 is further purified by the purifier 6, and the purifier 6 further washes out the impurity ions in the water, thereby improving the purity of the water flowing out of the water purifier, so as to achieve more thorough and effective cleaning of the concentration column 21, and realize the need to purchase additional pure water for cleaning operations, which is more conducive to reducing the connection of external pipelines.

[0025] Purifier 6 functions to remove anions and cations from the water flowing through it. Purifier 6 can be implemented using conventional equipment capable of removing anions and cations from water. For example, EDI (electrodeionization, also known as continuous electro-deionization) technology can be used for water purification, as described in Chinese Patent Publication Nos. CN207047024U and CN213595947U. This description and limitation are omitted here.

[0026] In one embodiment, in the pure water trace ion determination device in the cleaning mode, the cleaning container 32, the third multi-way switching valve 3, the second chromatographic pump 31, the fourth multi-way switching valve 4, the second multi-way switching valve 2, the concentration column 21 and the waste liquid container 5 are connected in sequence.

[0027] Specifically, such as Figure 1 As shown, before conducting pure water detection of the sample, the detection flow path of the trace ion measurement device can also be preliminarily cleaned with pure water. The pure water is transported to the second chromatographic pump 31 through the third multi-way switching valve 3. After the interior of the second chromatographic pump 31 is cleaned with pure water, the pure water output from the second chromatographic pump 31 flows into the fourth multi-way switching valve 4 and the second multi-way switching valve 2 in sequence and is transported to the concentration column 21 for cleaning, and finally the waste liquid is discharged from the second multi-way switching valve 2 to the waste liquid container 5.

[0028] Among them, the cleaning liquid output from the cleaning container 32 flows into the second chromatography pump 31 through the third multi-way switching valve 3; the cleaning liquid output from the second chromatography pump 31 flows through the third multi-way switching valve 3, the fourth multi-way switching valve 4, and the second multi-way switching valve 2 in sequence and flows into the concentration column 21; the cleaning liquid flowing out of the concentration column 21 flows into the waste liquid container 5 through the second multi-way switching valve 2.

[0029] In one embodiment, in the pure water trace ion determination device in the rinsing mode, the injection needle 12, the first multi-way switching valve 1, the second multi-way switching valve 2, the third multi-way switching valve 3, the second chromatographic pump 31, the fourth multi-way switching valve 4 and the waste liquid container 5 are connected in sequence.

[0030] Specifically, because the purity of the pure water sample being tested is very high, and therefore higher than that of ordinary purified water, the pure water sample can be used to rinse the detection flow path of the trace ion measurement device again before being delivered to the concentration column 21, thereby more effectively cleaning the detection flow path.

[0031] The pure water sample is sucked in through the injection needle 12 and flows through the first multi-way switching valve 1, the second multi-way switching valve 2, the third multi-way switching valve 3 and the fourth multi-way switching valve 4 in sequence, and is finally output from the fourth multi-way switching valve 4 and discharged into the waste liquid container 5.

[0032] After being rinsed with pure water samples, the trace ion determination device can more effectively and clearly detect the residual ions in the flow path and related pipelines, which is more conducive to improving the detection accuracy of pure water samples.

[0033] Among them, the sample solution output by the injection needle 12 passes through the first multi-way switching valve 1, the second multi-way switching valve 2, and the third multi-way switching valve 3 in sequence and enters the second chromatographic pump 31; the sample solution output from the second chromatographic pump 31 flows into the waste liquid container 5 through the third multi-way switching valve 3 and the fourth multi-way switching valve 4.

[0034] In one embodiment, in the pure water trace ion determination device in enrichment mode, the injection needle 12, the first multi-way switching valve 1, the third multi-way switching valve 3, the second chromatographic pump 31, the fourth multi-way switching valve 4, the second multi-way switching valve 2, the concentration column 21 and the waste liquid container 5 are connected in sequence.

[0035] Specifically, after the detection flow path of the trace ion measurement device is rinsed with sample pure water, the sample can be injected through the injection needle 12 for enrichment using the concentrator column 21. The pure water sample is drawn in through the injection needle 12 and flows sequentially through the first multi-way switching valve 1, the second multi-way switching valve 2, the third multi-way switching, the second chromatographic pump 31, and the fourth multi-way switching valve 4. The pure water sample output from the fourth multi-way switching valve 4 is then delivered to the second multi-way switching valve 2 and enters the concentrator column 21 for enrichment.

[0036] Among them, the sample solution output by the injection needle 12 passes through the first multi-way switching valve 1, the second multi-way switching valve 2, and the third multi-way switching valve 3 in sequence and enters the second chromatographic pump 31; the sample solution output from the second chromatographic pump 31 passes through the third multi-way switching valve 3, the fourth multi-way switching valve 4, and the second multi-way switching valve 2 in sequence and flows into the concentration column 21; the sample solution flowing out of the concentration column 21 flows into the waste liquid container 5 through the second multi-way switching valve 2.

[0037] Among them, during the enrichment process, the injection volume of the injection needle 12 can be controlled by the second chromatographic pump 31, and then the injection volume of the pure water sample can be calculated. In this way, there is no need to configure a large-scale quantitative container, and a sufficient amount of pure water sample can be injected according to the enrichment requirements to the maximum extent to meet the requirements of accurate detection of pure water samples.

[0038] In one embodiment, in the pure water trace ion determination device in elution mode, the first chromatographic pump 22, the second multi-way switching valve 2, the concentration column 21, the first multi-way switching valve 1, the quantitative loop 11 and the chromatographic column 13 are connected in sequence.

[0039] Specifically, after the pure water sample is enriched by the concentrator column 21, the concentrator column 21 can be eluted with an eluent. Driven by the first chromatographic pump 22, the eluent is delivered through the second multi-way switching valve 2 and into the concentrator column 21. The eluent elutes the ions enriched in the concentrator column 21. The eluted ions follow the eluent into the quantitative loop 11 and ultimately enter the chromatographic column 13 for separation and measurement.

[0040] Among them, the eluent output by the first chromatographic pump 22 flows into the concentration column 21 through the second multi-way switching valve 2 in sequence; the eluent output from the concentration column 21 flows into the quantitative ring 11 through the second multi-way switching valve 2 and the first multi-way switching valve 1; the eluent output from the quantitative ring 11 flows into the chromatographic column 13 through the first multi-way switching valve 1.

[0041] In addition, if Figure 5As shown, during the ion chromatography analysis, when a standard sample needs to be introduced, the first multi-way switching valve 2 is actuated to connect the injection needle 12, the quantitative loop 11 and the third chromatographic pump 14 in sequence, and the standard sample is injected through the injection needle 12, and the excess standard sample is transported to the waste liquid container 5 through the third chromatographic pump 14; then, the switching is switched to Figure 2 In the state, the first chromatographic pump 22 delivers the eluent to deliver the standard sample in the quantitative loop 11 to the chromatographic column 13 of the ion chromatograph for measurement.

[0042] The specific process of the ion chromatograph performing ion chromatographic analysis on the liquid in the chromatographic column refers to the analysis process of a conventional ion chromatograph and is not limited here.

[0043] The present application also provides a detection method of the above-mentioned device for determining trace ions in pure water, comprising: an injection mode, a flushing mode, an enrichment mode, and an elution mode; In the injection mode, the sample solution is injected into the quantitative loop 11 through the injection needle 12; In the cleaning mode, the cleaning liquid flows through the third multi-way switching valve 3, the second chromatography pump 31, the fourth multi-way switching valve 4, and the second multi-way switching valve 2 in sequence and enters the concentration column 21 for cleaning treatment; In the rinse mode, the sample solution is sucked in through the injection needle 12 and flows sequentially through the first multi-way switching valve 1, the second multi-way switching valve 2, the third multi-way switching valve 3, the second chromatographic pump 31, and the fourth multi-way switching valve 4; In the enrichment mode, the sample solution is injected into the concentration column 21 through the injection needle 12; In the elution mode, the eluent flows through the first chromatographic pump 22 , the second multi-way switching valve 2 , the concentration column 21 , the first multi-way switching valve 1 , the quantitative loop 11 and the chromatographic column 13 in sequence.

[0044] By configuring multiple multi-way switching valves, the flow path can be switched according to different working modes. The first chromatographic pump is used to enrich sufficient ions in pure water on the concentration column, and then the eluent is transported by the first chromatographic pump to elute the concentration column and transport it into the chromatographic column for ion chromatography detection. As for the second chromatographic pump, during use, on the one hand, the cleaning liquid can be transported by the second chromatographic pump to clean the multi-way switching valve and the concentration column. On the other hand, after the multi-way switching valve is switched, the second chromatographic pump injects the pure water to be tested through the injection needle to use the pure water sample to clean the multi-way switching valve and the connecting pipes between the multi-way switching valves. In this way, it is possible to avoid large errors in the actual detection process due to excessive ion content in the cleaning liquid during the cleaning process. The second chromatographic pump is used to rinse the multi-way switching valve and the connecting pipes with the pure water sample to be tested to minimize the influence of external ions, and to maximize the ions enriched in the concentration column from the pure water sample to be tested, thereby meeting the detection requirements of trace ions in pure water and improving the detection accuracy.

[0045] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A device for measuring trace ions in pure water, characterized in that: include: a first multi-way switching valve, wherein the first multi-way switching valve is provided with a quantitative loop, an injection needle and a chromatographic column, and the injection needle, the quantitative loop and the chromatographic column are respectively connected to corresponding connection ports of the first multi-way switching valve; a second multi-way switching valve, wherein the first multi-way switching valve is provided with a concentrating column and a first chromatographic pump, the concentrating column and the first chromatographic pump are respectively connected to corresponding connection ports of the second multi-way switching valve; the second multi-way switching valve is also connected to the first multi-way switching valve; a third multi-way switching valve, wherein the third multi-way switching valve is provided with a second chromatographic pump and a cleaning container, wherein the cleaning container is configured to store cleaning water; the second chromatographic pump and the cleaning container are respectively connected to corresponding connection ports of the third multi-way switching valve; and the third multi-way switching valve is also connected to the second multi-way switching valve; a fourth multi-way switching valve, the fourth multi-way switching valve being connected to the second multi-way switching valve and the third multi-way switching valve, respectively; the fourth multi-way switching valve being configured to switch the liquid output from the injection needle or the cleaning container to flow to the concentrating column or the waste liquid container; A purifier is further provided between the fourth multi-way switching valve and the third multi-way switching valve.

2. The device for measuring trace ions in pure water according to claim 1, wherein In the cleaning mode, the cleaning container, the third multi-way switching valve, the second chromatographic pump, the fourth multi-way switching valve, the second multi-way switching valve, the concentration column and the waste liquid container are connected in sequence.

3. The device for measuring trace ions in pure water according to claim 2, wherein: The cleaning liquid output from the cleaning container flows into the second chromatographic pump through the third multi-way switching valve; The cleaning liquid output from the second chromatographic pump flows through the third multi-way switching valve, the fourth multi-way switching valve, and the second multi-way switching valve in sequence and flows into the concentration column; The cleaning liquid flowing out of the concentrating column flows into the waste liquid container through the second multi-way switching valve.

4. The device for measuring trace ions in pure water according to claim 1, wherein In the rinse mode, the injection needle, the first multi-way switching valve, the second multi-way switching valve, the third multi-way switching valve, the second chromatographic pump, the fourth multi-way switching valve and the waste liquid container are connected in sequence.

5. The device for measuring trace ions in pure water according to claim 4, characterized in that The sample solution outputted by the injection needle passes through the first multi-way switching valve, the second multi-way switching valve, and the third multi-way switching valve in sequence and enters the second chromatographic pump; The sample solution output from the second chromatographic pump flows into the waste liquid container through the third multi-way switching valve and the fourth multi-way switching valve.

6. The device for measuring trace ions in pure water according to claim 1, wherein: In the enrichment mode, the injection needle, the first multi-way switching valve, the third multi-way switching valve, the second chromatographic pump, the fourth multi-way switching valve, the second multi-way switching valve, the concentration column and the waste liquid container are connected in sequence.

7. The device for measuring trace ions in pure water according to claim 6, wherein: The sample solution outputted by the injection needle passes through the first multi-way switching valve, the second multi-way switching valve, and the third multi-way switching valve in sequence and enters the second chromatographic pump; The sample solution output from the second chromatographic pump flows into the concentration column through the third multi-way switching valve, the fourth multi-way switching valve, and the second multi-way switching valve in sequence; The sample solution flowing out of the concentrating column flows into the waste liquid container through the second multi-way switching valve.

8. The device for measuring trace ions in pure water according to claim 1, wherein: In the elution mode, the first chromatographic pump, the second multi-way switching valve, the concentration column, the first multi-way switching valve, the quantitative loop and the chromatographic column are connected in sequence.

9. The device for measuring trace ions in pure water according to claim 8, characterized in that The eluent output by the first chromatographic pump flows into the concentration column through the second multi-way switching valve in sequence; The eluent output from the concentrating column flows into the quantitative loop through the second multi-way switching valve and the first multi-way switching valve; The eluent output from the quantitative loop flows into the chromatographic column through the first multi-way switching valve.

10. A detection method for the device for measuring trace ions in pure water according to any one of claims 1 to 9, characterized in that: include: Injection mode, flushing mode, enrichment mode and elution mode; In the injection mode, the sample solution is injected into the quantitative loop through the injection needle; In the cleaning mode, the cleaning liquid flows through the third multi-way switching valve, the second chromatographic pump, the fourth multi-way switching valve, and the second multi-way switching valve in sequence and enters the concentrating column for cleaning; In the rinse mode, the sample solution is sucked in through the injection needle and flows through the first multi-way switching valve, the second multi-way switching valve, the third multi-way switching valve, the second chromatographic pump, and the fourth multi-way switching valve in sequence; In the enrichment mode, the sample solution is injected into the concentrator column through the injection needle; In the elution mode, the eluent flows through the first chromatographic pump, the second multi-way switching valve, the concentration column, the first multi-way switching valve, the quantitative loop and the chromatographic column in sequence.

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